Why is My car making a diesel truck sound after it warms up

Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your vehicle. If your Cobalt sounds like a diesel truck after warming up and the oil light is coming on, it could be a sign of low oil pressure. This might happen if there's an issue with the oil pump, a clogged oil filter, or even a blockage in the oil passages. The ticking or rattling sound could indicate that the engine isn't getting enough oil to lubricate the moving parts, which is why the oil light is showing up. Checking the oil level would be a good first step. I'd recommend not driving the car further and getting it inspected as soon as possible to avoid engine damage. If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!